What are the rashes on my

limbs ?( 21/6/2015 HKDU PMH )

Dr. Lee Tze Yuen

M.D.(H.K.) F.R.C.P.(Edin.) F.H.K.A.M.(Med.)

Hon. Clinical Associate Professor

Faculty of Medicine H.K.U.

Pigmented band of finger nail

History:

A teenage boy had a brownish band

running from the cuticle to the distal

edge of his finger nail.

Question:

Should a biopsy be taken from his nail?

Longitudinal melanonychia (甲黑)

Causes: normal variation --Asians 11%

1. increased melanin synthesis

2. tumors of melanocytes

beneign – naevus

malignant – malignant melanoma

C/F: Tan, brown or black longitudinal streak

within nail plate.

Longitudinal melanonychia

Signs suggestive of possible malignancy:

1. widening or darkening of the pigmented band

2. peri-ungal spread of pigmentation to proximal

or lateral nail fold (Hutchinson’s sign)

3. ill-defined, irregular lateral border

4. band is black or variegated

5. lesion begins after 50

Rashes at flexures

History:

A 13 years old boy has long history of dermatitis

requiring frequent use of topical steroids. His

mother was very worried that the steroid may affect

his normal growth.

Questions:

“ Dr., can you do something about it? “

Non-steroidal immunomodulators

( e.g. tacrolimus / pimecrolimus )

Mechanism: inhibits T cell proliferation

Adantage: do not have side effects of steroids

useful in dermatitis :

- intermittent use to prevent flares

- at eye-lids, face and neck

-Rx of early lesions

- should not be used for children <2

Non-steroidal immunomodulators

( e.g. tacrolimus /pimecrolimus )

Side effects:

- burning sensation --very common

- increased sensitivity to heat and cold

- flu-like symptoms

- infections like herpes simplex, herpes

zoster, impetigo

- folliculitis

Linear itchy rashes at

thigh

History:

A 45 years old man complained of a linear pigmented

lesion at his thigh.

It appeared to diminish a bit after treatment with

steroid cream but reappeared soon after it was

discontinued.

Question:

“Dr., what is the linear rash at my thigh?”

Lichen striatus

A form of eczema arranged in a linear

form

- Responds well to topical steroids

- Easily confused with linear epidermal

naevus (a beneign tumour arising from

epidermal cells)

Red weepy rashes at groin

History:

A 62 years old man complained of itchy, red,

weep rashes at his left groin.

Questions:

1. What physical signs were shown in his

lesion?

2. What is your diagnosis?

Radiodermatitis

Physical signs:

Erythema, telangiectasia, fibrosis, ulceration,

pigmentary changes, well-demarcated or

angulated borders

Rx:

1. symptonatic Rx with topical steroids

2. watch out for malignant and prenalignant

conditions

Wide spread erosions

History:

A teenage school boy has long history of itchy

rashes at his trunk and limbs.

He had sudden onset of low grade fever,

malaise and wide spread bubbles and

erosions at his upper limbs and trunk

Question:

What do you think is the most likely causative

agent ?

Eczema herpeticum

Herpes simplex complicating dermatitis.

C/F: similar to herpes simples but much

more severe and extensive.

Rx: requires prompt and energetic

treatment

Intensely itchy nodules

History:

A desparate 67 years old retired merchant

complained of intensely itchy lumps on his

limbs and trunk.

They responded poorly to all the medications

given so far.

Questions:

1. What is your diagnosis?

2. What is your Rx of choice ?

Nodular prurigo (結節性癢疹)

Definition: A chronic inflammatory

disease of the skin characterized by

widespread itchy nodular lesions.

Lesions: multiple, discrete, grossly

lichenified papules and nodules with ill-

defined borders and marked excoriation

Mx of nodular prurigo

(結節性癢疹)

1. Steroids:

a) topical use of very potent steroids

b) intra-lesional steroids

2. Supportive measures

e.g. antihistamines, cutting of nails,

antibiotics…

Sharp pain and linear red

rashes

History:

A young diver was seen at the AED.

He complained of itchy and painful rashes at

his wrist since this morning.

Questions:

1. What are the common causes of linear

lesions at the wrist?

2. How should this patient be treated?

Jelly fish dermatitis

Mechanism: toxins from nematocytes

C/F:

- sudden sharp pain followed by appearance

of characteristic rashes

P/E:

- linear, erythematous lesions with papules

or blisters on top

Jelly fish dermatitis

Treatment:

1. Soak in hot (not scalding ) water to

denature proteins from nematocytes

2. Use of potent topical steroids,

analgesics and antihistamines

Scaly feet for years

History:

This middle age man had dry scaly rashes of his feet for many years. The rashes were neither itchy nor painful.

He had tried various moisturizers and topical steroids which gave unsatisfactory response.

Question:

Suggest one important diagnostic test for this

patient.

Hyperkeratotic type of tinea pedis

Often not itchy—patient may not know that

they had the infection for years!

C/F:

- affecting the soles, heels and sides of feet

- more pronounced at lines and creases

Common organism: trichophyton rubrum

Itchy painful rashes of fingers

History:

A 57 years old H.W. complained of itchy and

painful rashes her fingers.

Questions:

1. What abnormal signs do you notice in this

patient’s hands?

2. How would you manage this patient?

Chronic paronychia

(慢性甲溝炎)

Signs of chronic paronychia:

- loss of cuticle

- periungal erythema

- periungal swelling

- gap between nail plate and nail fold

- others: nail deformities

pus on compression

- often associated with changes of chronic

dermatitis

Chronic paronychia

(慢性甲溝炎)

Management of chronic paronchia:

1. Keep hands dry—most important

2. Topical anti-fungal + mild steroid

e.g. 1 % hydrocortisone and clotrimazole

3. Rx of chronic dermatitis

Dr., Is this “食肉菌 “ ?

History:

A young athlete was very worried because

the superficial parts of his toes and soles

were gradually “ being eaten by some

unknown organism”.

Questions:

1. Is this “食肉菌” ?

2. What is your treatment of choice?

Pitted keratolysis

(凹陷性角質層分離)

A superficial bacterial infection of the toes and soles by corynebacteria.

They produce proteolytic enzymes which digest keratin, giving rise to superficial, circular, punch-out erosions.

Rx:

A) topical: fusidic acid, clotrimazole,

Whitfield’s ointment

B) oral antibiotics e.g. erythromycin

Painful papule at sole

History:

This 18 years old university student

complained of a painful lump at his heel.

“ Can you remove the wart for me, Dr.?”

Question:

What would you do?

Corn of sole (雞眼)

Corn is a localised hyperkeratosis of the skin due to repeated pressure or trauma.

Corn Vs Wart:

1. Corn always appears at pressure points

2. Paring - corn becomes more and more

normal looking after being pared.

- warts showed dark spots or bleeding

points

Asymptomatic scaly palms

History:

A 20 years old clerk felt socially embarrassed because of recurrent episodes of scaly rashes on his hands. The lesions were neither itchy nor painful.

Repeated scrappings for fungus were negative.

Question:

“ What is the cause of the scaling? ”

Keratolysis exfoliativa

C/F:

- superficial exfoliation of palms and soles

- usually asymptomatic

- no inflammation

- culture for fungus negative

Path: a mild form of dermatitis

Rx: - reassurance

- emollients or mild steroids

- Whitfield’s ointment

Lumps at dorsum of hand

History:

The owner of a shop selling tropical fishes noticed a red, slightly tender lump on his hand for 9 months.

Rx with ampiclox and topical anti-fungal cream showed no response.

Questions:

1. What investigation would you perform for this

patient?

2. What is the treatment of choice for him?

Lumps at dorsum of hand

DDx: fish tank granulosum, sporotrichosis,

tuberculosis verrucosa cutis,

skin tumors

Ix: a) punch biopsy for histopathological

examination and

b) culture for AFB

Fish tank granuloma

(魚池肉芽腫)

- also known as swimming pool granuloma

- an infection caused by atypical

mycobacterium, M. marinum

- mode of transmission:

a) fish tank b) swimming pool

- sites : hands, elbows, knees

- Rx: a) septrin or doxycycline

b) rifampicin and ethambutol

Itchy rashes on feet

History:

A 45 years old executive complained of itchy red rashes at the dorsa of her feet every time she had trips abroad.

Examination showed erythematous rashes at the dorsa of her feet.

Questions:

1. What do you notice about the distribution

of the rashes?

2. What is your diagnosis?

Shoe contact dermatitis

(鞋之接觸性皮炎)

C/F:

a) changes of dermatitis

b) convex surfaces affected

infolded area (e.g. flexural creases of toes,

insteps ) spared

Common allergens: rubber accelerators,

chromium in leathers,

adhesives…

Itchy painful rashes of hands

History:

A young boy complained of itchy, dry and painful rashes at the dorsa of his hands.

He was noticed to have cystic acne and his lips were dry and scaly.

Questions:

1. What leading questions would you ask the

patient so as to find out the cause of the

rashes?

2. What is the treatment of choice for his rashes?

Asteatotic dermatitis

(乾燥性皮炎)

1. Cystic acne together with dry and scaly

lips suggested that he was having treatment

with isotretinoin ( Roaccutane, Oratane ).

Asteatotic dermatitis of hands is a very

common side effect of isotretinoin.

2. Rx of choice : 1 % hydrocortisone or

mometasone ointment

Doxycycline and isotretinoin

History:

This patient was taking oral doxycycline

from the dispenser at the same time.

Question:

What is your comment?

Cystic acne and isotretinoin

Tetracyclines must not be prescribed together

with isotretinoin !

Both can cause raised intracranial pressure!

Erythromycin can be taken with isotretinoin.

Generalised skin rashes

History:

A 23 years young man noticed malaise, headache, and low grade fever for a few days followed by the appearance of non-itchy, erythematous rashes at his palms, soles, limbs and trunk.

Question:

What is the most important investigation one

should perform for the patient?

Secondary syphilis

(二期梅毒)

Investigation: V.D.R.L. always positive

at this stage

Important to consider secondary syphilis as a possibility in all patients with generalised, symetrical lesions.

This stage is highly contagious--- do not touch the lesions with your hands!

Secondary syphilis

(二期梅毒)May mimic a large no. of skin diseases

Morphology :

- pinkish exanthema at early stage

- skin lesions: macular, papular,

papulosquamous , pustular, acneform

- mucous membranes: mucous patches,

papular lesions

- scalp: diffuse hair loss,“moth-eaten”alopecia

Thank you very much

for your attention !